The compounds of the instant invention are in the class of molecules that have been called "crown ethers". The crown ethers were originally named by Charles Pedersen who revealed in 1967 in a paper published in the JOURNAL OF THE AMERICAN CHEMICAL SOCIETY at volume 87, page 7071, that macrocyclic polyether compounds could bind cations. From the appearance of their molecular models, Pedersen said that the rings appeared to crown the cations when they complexed therewith. The systematic nomenclature for crown ethers is fairly complicated and the name crown has thus found very wide use.
Crown ether compounds are commonly named using a number-crown-number sequence. The first number identifies the total number of contiguous atoms which comprise the macroring. Crown is the informal family name and indicates the presence of repeating CH.sub.2 CH.sub.2 O units. The second number designates how many heteroatoms are present in the macroring. A cycle of six (--CH.sub.2 CH.sub.2 O--) units would be called 18-crown-6.
The compounds of the instant invention also comprise the subclass ethers called the lariat ethers first described in Gokel, G. W.; Dishong, D. M.; Diamond, C. J.; J. CHEM. SOC., CHEM. COMMUN., 1980, 1053. These are compounds which have a macroring bound to one or more pendant sidearms and are described in detail in U.S. Pat. No. 4,474,963 issued Oct. 2, 1984, U.S. Pat. No. 4,436,664 issued Mar. 3, 1984 to George W. Gokel and U.S. Pat. No. 4,597,903 issued to George W. Gokel and Vincent J. Gatto.
In the instant invention, we demonstrate structures having oxygen-or oxygen- and nitrogen-containing macrorings bound to chlesteryl or dihydrocholesteryl residues. The steriodal sidearms are attached either at carbon on the macroring 2-position of an all-oxygen ring or at the nitrogen of an azamacrocycle. When the sidearm is attached at carbon, these structures are called carbon-pivot lariat ethers. When the sidearm is attached to the nitrogen atom, the structures are called nitrogen-pivot lariat ethers.
The macrocyclic polyether rings contain heteroatoms such as oxygen or nitrogen. As such, they are fairly polar residues. When bound through some sort of spacer or connector unit to a steroidal system, the overall character of the molecular is amphiphilic. The steroidal residue, which usually contains more than twenty-five carbons, is extremely lipophilic. In addition, the steroidal residue is large and nearly flat but slightly helical. The large number of carbon-hydrogen bonds in the steroid nucleus make it nonpolar or oleophilic (lipophilic) and thus insoluble in water under normal circumstances.
The steriodal nucleus can be attached to the macrocyclic polyether ring in several ways. The general approach is illustrated schematically below: